Astronomy chapter 3

  1. rotation
    motion around an axis passing through the rotating body
  2. revolution
    orbital motion about a point located outside the orbiting body
  3. ecliptic
    the apparent path of the sun around the sky
  4. vernal equinox
    the place on the celestial sphere where the sun corsses the celestial equator moving northward. Also, the time of the year when the sun crosses this point, about march 20, and spring begins in the northern hemisphere
  5. summer solstice
    the point on the celestial sphere where the sun is at its most notherly point.
  6. autumnal equinox
    the point on the celestial sphere where the sun crosses the celestial equator going southward
  7. winter solstice
    the point on the celestial sphere where the sun is fathest south
  8. perihelion
    the orbital point of closest approach to the sun
  9. aphelion
    the orbital point of greatest distance from the sun
  10. lunar eclipse
    the darkening of the moon when it moves through earth's shadow
  11. umbra
    the region of a shadow that is totally shaded (pg 30)

    Image Upload 2
  12. penumbra
    the portion of a shadow that is only partically shaded Image Upload 4
  13. totality
    the period of total eclipse
  14. sidereal period
    the time a celestial body takes to turn once on its axis or revolve once around its orbit relative to the stars
  15. synodic period
    the time a solar system body take to orbit the sun once and return to the same orbital period referenced to Earth.

    for the moon, this is the time for the moon to orbit.
  16. solar eclipse
    the even that occurs when the moon passes directly between the sun, blocking our view of the sun
  17. photosphere
    the bright visible surface of the sun

    Image Upload 6
  18. chromosphere
    bright gases just above the photosphere of the sun
  19. corona
    on the sun, the faint outer atmosphere composed of low-density, high temperature gas
  20. prominence
    eruption on the solar surface; most visible during total solar eclipses
  21. diamond ring effect
    during a total solar eclipse, the momentary appearance of a spot of the photosphere at the edge of the moon, producing a brilliant glare set in the silvery ring of the corona
  22. Saros cycle
    an 18 year, 11.33- day period after which the pattern of lunar and solar eclipses repeats
  23. Milankovitch hypothesis
    suggestions that Earth's climate is determined by slow periodic changes in the shape of this orbit, the angle of its axsis and precession
Card Set
Astronomy chapter 3
keys terms and concepts